Cyclic weather conditions, geology, and soil conditions combine to create temporary bodies of water where plants and wildlife thrive. Boggs Lake Preserve contains a large vernal pool which forms in an ancient volcanic crater on the side of Cobb Mountain during the rainy season each year. This vernal pool is unique in that it is surrounded by a forest of Black Oak and Ponderosa Pine rather than the typical grasslands.

Nature's peace will flow into you as sunshine flows into trees. ~ John Muir

Two Season Climate

Cobb Mountain, in southern Lake County, California, is the highest peak in the Mayacamas range. With cool, wet winters and hot, dry summers; the region is known for its warm days, cool nights, and low humidity. In January, during the wet season, the average high temperature is 54 degrees and the average low temperature is 26 degrees. Arid August temperatures average a high of 96 degrees and a low of 57 degrees. The average rain fall on Cobb Mountain is 60 inches a year.

A few minutes ago every tree was excited, bowing to the roaring storm, waving, swirling, tossing their branches in glorious enthusiasm like worship. But though to the outer ear these trees are now silent, their songs never cease. ~John Muir

Geology, Soil, and And All That Rain

Boggs Lake Preserve contains a 100 acre vernal pool. During the fall and winter rains, run off from Cobb Mountain is trapped by a volcanic crater which lies at 2787 feet elevation. The rain water cannot permeate the layers of ash and basalt which line the crater so it "pools up." No creeks or springs feed the vernal pool and no water flows out of it. Thus the vernal pool slowly grows during the wet season and quickly evaporates during the dry season.

Winter

Summer

Learn More About Vernal Poolsplease click the arrow buttons infront of the link title

Find the answers to your questions about vernal pools

Good definitions of vernal pools

It's Time To Get Down And Dirty!

Vernal pool formation experimentPercolation: the process of water moving downward through openings in the soil

Materials:* Two colanders* Two large dinner plates* Soil, potting mix or from the yard* Modeling clay* Ash or cinders* Small pieces of basalt or "lava rock" (available at home improvement stores)* A plant mister or squirt bottle* Two cups of water

Places the colanders atop plates. Line the bottom of colander one with soil. Knead ash or cinders into the modeling clay. Pat the modeling clay into a circle and press it into the bottom of colander two. Stud the clay with a few pieces of basalt. Mist each colander with one cup of water. Observe what occurs. Discuss your findings. Record and draw about what you have learned in your field journal.

Temperature Conversion Calculator

This calculator will convert a Fahrenheit
temperature into its Celsius equivalent -- or visa versa.